(Jeff Abbott is a regular contributor at The Pen Addict. You can find more from Jeff online at Draft Evolution and Twitter.)

The HMM Rule/One pen and ruler is a unique design that may appeal to the design crowd more than the normal pen enthusiast. The industrial design and unique aesthetic is certainly interesting, but that unique-ness may detract from the actual writing experience.

Now, this isn't the first time you've probably seen a design like this for a pen. Remember the CW&T Pen Type-A? Similar design, similar target audience. While the Pen Type-A is certainly quite a bit more expensive than the Rule/One, and they both work with different types of refills (Uniball Signo vs. Pilot Hi-Tec-C), I have a hard time recommending the Rule/One due to a few design problems that make me unsure of the product.

First, let's run through the features of this pen. As you can see, the pen is housed in a ruler/straightedge case and stays connected by magnets. The ruler is five inches on one side, and 13 centimeters on the other. At the top of the ruler section, there's a removable nut that allows you to install an included stylus tip or lanyard loop. It uses a standard flat-head screwdriver to remove/install the standard nut, and installation of the other optional pieces is a breeze.

The pen is nicely weighted and has a nice accent color (black, orange, or silver) at the tip. The rest of the pen (and the ruler) is a textured, black aluminum that feels and looks great. The pen uses Uniball Signo refills, so your options for replacement are great. A black 0.5mm refill is included with the pen, and replacing it is an easy task of unscrewing the tip, removing the refill, removing the circular magnet sleeve from the refill, and putting everything back together again with the new refill.

The teardrop shape of the ruler is helpful when using it as a straightedge, and also creates a lot of visual interest when it's laying on your desk. The aesthetic design of this instrument is very pleasing, and I'm sure it will catch the eyes of your coworkers quite often. It's certainly a conversation piece.

Unfortunately, the topics of conversation might lean toward the negative depending on how you view the writing capabilities of this pen along with the overall fit and finish of the entire thing.

The pen can be somewhat uncomfortable to write with, but this is really a personal preference. I didn't like the Pen Type-A for this same reason. I prefer a tapered, conical grip/tip for my pens, not a sudden drop from one large diameter to a much smaller one.

But, my number one complaint with this pen, and the overall reason why I can't recommend it, is the amount of wobble and looseness present when you "cap" the pen into the ruler casing. It uses magnets to secure the two pieces together, and they just aren't strong enough to make a sturdy fit. It easily falls out, makes noise when handling, and turns easily while closed. I have a couple other pens that rely on magnets to close the pen, and they are rock solid. I have to wonder if stronger magnets would solve this problem.

Another part of this "wobble" issue is the size of the hole that houses the pen tip. It's way too large. If the size was closer to the diameter of the pen tip, this would also go a long way in securing the pen when in the closed position. But, in reality, it's about two times too large, and that allows a lot of wobble.

When putting this pen in a bag for a short commute, I've never gotten it out in one piece. They always separate at some point, and it's not like I'm hiking over a mountain, either. From desk to bag, a short car ride and walk to the office, and then back out of the bag. Two pieces — every time.

The fact that a lanyard loop is included is somewhat confusing to me considering the weak magnet problem. If you use this with a lanyard, I think the pen will stay attached as designed about 75% of the time, but it will almost certainly come undone fairly regularly. I haven't really tested this much because I'm worried of losing the pen.

Needless to say, this pen has been relegated to "desk only" duty, which is a shame. It's a handsome pen, and it has great utility. It's unfortunate that a couple of key design problems hinder this pen from realizing its full potential. Maybe in version two those faults might be corrected.

At $60, the price is a bit too steep to allow for this kind of design flaw, especially when it's part of the core functionality of the whole instrument. It's a great concept, but the delivery just isn't there yet.

(JetPens provided this product at no charge to The Pen Addict for review purposes.)

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